Mechanical automatic stop for turret lathes



April 1950 J. G. MADSON 2,503,283

MECHANICAL AUTOMATIC STOP FOR TURRET LATHES Filed May 23, 1945 5 Sheets-Sheet 1 FIG.2.

JQHN G. MADSQN April ll, 1950 G. MADSON MECHANICAL AUTOMATIC STOP FOR TURRETLATHES 3 Sheets-Sheet 2 Filed May 23, 1945 JOHN G. MADSON April 11, 1950 J. G. MADSON 2,503,283

' MECHANICAL AUTOMATIC STOP FOR TURRET LATHES Filed May 23, 1945- 3 Sheets-Sheet 3 FIG 8 JOHN G. MADSON Patented Apr. 11 1956 MEGHANIQALAUTOMATIQ STO EQ TURRET LATHES.

John George M'adson, United. States Navy ApplicatiomMay 2c, 1945, Serial No. 595,31

(Granted unearths: a i March 1.8 :3 as amenderllv April 30, 1928-; 37:0: G 1

1 Claim.

This invention relates. to lathcs; and m re-specifically to an automatic stop; for use. with lathes of the type which employ a power feed.

In the lathe illustrated herein, the workis; fixed at one end in a chuck for rotation about itslongitudinal axis, and abutting tool is. fixed a: turret which is adapted? to. he; moved progressively to? ward the chuck during the cutting. onerationi It is to be observed, however, that the turret may be fixedand the chuck moved to advance the work toward the tool, and accomplish the same result. As thus set 111 he tool is a iustably positioned at a given radial distance fromthe axis of the work so as to. take off the desired amountof stock from its surface, and as. the WOIK. mov s along, the turned-down or finished portion-there.- of passes through an, opening formed: in the top ret.- To prevent the finished work from bending due to the lateral thrust produced by the cutting tool, there are provided a pair of bearings. adjacent to the tool which are adapted tan entially to engage the surface of thefinished work atsllbs stantially equally spacedpoints opposite 'theeliOQl, The cutting edge of the tool: is; slightly ahead of the bearings so that the; unturned stock neve quite reaches the hearings. If; however, thetooi breaks or slips out of place, theunturned' portion of the work will strike the bearings dueto; the continued. forward feed of the.- turret and smash them.

It is an object of this invention to provide an automatic stop adapted to. declutch a power lathe if the cutting tool breaks or slips out of position, to prevent damage tothe lathe tool kit which consists of the tool and bearings referred, to above, the stop being of simple design and readily adaptable to existing equipment without undue change therein.

In a lathe of the type referred to, there is a.

work-piece holder in the nature of a chuck rotatable about a horizontal axis, a turret, adapted to. hold a tool, the turret being movable toward the. work holder or chuck, bearings, associated, with the tool to engage the tooled work to prevent bending thereof due to the action of the tool, andthe invention resides in the combination with the aforesaid elements of means adjacent to. the plane of the end faces of the bearings tangent to a circle defined, by the edges of the cutting tool and the points of tangency between the. tooled work and the bearings, the aforesaidv means. be ingadapted upon being engaged by a portion of. the work lying outside of said. circle tov stop, the lathe. comprises an arm arranged betweenthepla-neof More specifically, the aforesaid means.

. rodand retainingrlatch;

2 the end faces; of the. bearings and? a plane parallel thereto passing through the cutting edge of the tool in a position to be engaged by any: inregularity in the work, and to release a plunger which is. held; retracted thereby, theplunger when released, being adapted; to effect disengagement of a clutch which connects the lathe to a source of; power, so. that the lathe: will stop before: damage; is. done. to the bearings.

The invention will now be described with.- reference to, the: accompanying drawings; in: which:

Fig l is a top. view: oi the chuck andturret of a power lathe with which. mynovel automatic stop is used;

Fig. is aside: elevation. of the lathe showing part of the base and theturret;

Fig. 3; is. an enlarged segmental view of" a piece or work before and after turning; showing the relative positions of the cutting tool, bearings amd the work engaging: portion oil my'stop;

Fig; 4 is a fragmentary detail? of a latch for re, taining the. clutch in engagement;

Fig, ,5 is a.. plan. view of the: turret, drive gear housing and automatic; stop showii'igv the clutch Fig. 6 is a section through thestop mechanism sh wing a loededtoonditionzt F 7 is a sec ion th ough thesstopsmechan fim Showing. i a released condit n; and

ig;- 8 s. a r nsver -W Qfi'the: l he om he i e 8-8 of- Fig} sh wing the au m t c stoic mounted onthe-fage of the tool kit.

Referring to Fig. there; is shown; a. power lathe In comprising; abase 12,.a turret Mwhich s dapted tobe moved: al n parall t acks to;

8; y means 015 ascrew l-r8-towa d'a Stat oners chuck .lfl which saada ted tQ-hold a meteor work W atone end for rotation.about-itslongitud a1 ax With respect to a too fixe t t e but t. The turret l4. is six sided, is; hollow,- and dfam r'cal d spo d op n n s 2: h n pass ing, through. the center of. each pair. of parallelfaces through which thework-piece passes turret. advances toward the chuck. T e. toolkit which carries the cutting tool, is, indicated ail-2A and is fastened to, one of the fiacesof the-turret. Qther tools, may be fastened. to. the othenfaees of. the turretwhich maybe rotatedto, bring. any. one of the. tools into a position. to. operate? upon the work, however, only the onetool, which. will. be described hereinatter, is necessary tor a @Qm-r plete understanding of the. present.v inuention. Thetool. kitZAcomprisesa plate at boltedtoone face of the turret-over. one. opening 22. and has an opening. 23. thereinv concentric with, the o en,

' 3 ing 22. In the lower portion of the plate there is slidably mounted for movement in a horizontal plane, a slide member 28 to which there is adjustably fixed a cutting tool 30. Also slidably mounted in the plate 26 are a pair of slide members 32 and 34, Fig. 8, having mounted thereon bearings 36 and 38rotatable about horizontal axes normalto the plane of the plate 26. The slide members 32 and 34 are so arranged that they may be adjusted radially with respect to the axis of rotation of the chuck 20. If-the rough or unfinished work W is clamped in the chuck 20, Fig. 1, with its free end adjacentto the cutting tool 30 and then the cutter tool is adjusted to take off the desired amount from the surface of the work as it is rotated by the chuck, the pressure created during the cutting operation is such that it would deflect the work since it is supported only at one end, and hence, the surface obtained would not be true. To avoid this, and to insure an accurate tooling, the bearings 36 and 38 described, are adjusted radially inward to engage the finished surface F of the work, as indicated in Fig. 8, thereby to engage and support the work as it passes through openings 23 and 22 in the plate 26 and turret face respectively.

These bearings 36 and 38 are precision ground and damage to these bearings .is an expensive matter. As is clearly apparent from Figs. 3 and 8, if for any reason the tool 30 should be broken or become displaced so that it does not remove the metal to the depth for which the tool was initially set, the uncut portion of the work will strike these bearings 34 and 38 and damage them, because the bearings are set in at th same radial depth as the cutting tool andfeed forward regardless of the fact that the tool is not cutting properly.

It is to prevent such damage to the bearings that the automatic stop for the present invention was devised. This stop indicated generally by the reference character 40, comprises an arm 42 arranged adjacent to the bearings 34 and 38,

and as seen in Figs. 3 and 8, slightly in advance of the plane of the forward faces of the bearings and just back of a plane parallel thereto passing through the cutting edge of the tool. Hence, if the work W is not cut down to the diameter shown at F, the shoulder left between the reduced diameter F and the original diameter W will strike the arm 42 before it reaches the forward faces of the bearings 36 and 38. The arm 42 is fixed to a member 44, the latter being pivoted at 46 between the ends of a bracket 48, for tilting movement in a vertical plane running longitudinally of the lathe, the bracket in turn being secured by bolts 60 to the face of the plate 26. Clamped to the plate 26 by means of the afore said bracket 48, there is a cylindrical sleeve 52. The upper end of sleeve 52 is closed, Figs. 6 and '7, and the lower end is open and there is disposed therein, a plunger 54 to which there is fixed a rod 56 which extends through the upper closed end of the sleeve 52. ably urged toward the lower opened end of the sleeve 52 by a coil spring 58 surroundin the rod 56 between the rear surface'fill of ,the plunger 54 and the upper closed end 62 of the sleeve 52. A rod 64 is fixed transversely of the rod 56 and provides a hand-hold for drawing the plunger 54 into the sleeve 52 so that its lower surface 51 is flush with the end of the sleeve to compress the spring 58. As thus retracted, the plunger is in a cocked position and to hold it in this cocked position,

The plunger 54 is yieldthe lower end of the member 44 is provided with a hook 66 adapted to engage an annular recess 54 formed on plunger 54, an aperture 68 being provided in the wall of the sleeve 52 through which the hook projects. Th hook may be brought into engagement with the annular recess to cock the automatic stop by retracting the plunger against the spring 58 and tilting the member 44 so that the hook projects inwardly through the aperture 68. A spring 10 set into a recess 'H formed in the member 44 is adapted to bear against the surface of the sleeve 52 and yieldably to hold the member 44 in its cocked position. Below the sleeve 52 and plunger 54, there is disposed a horizontal lever 12 pivoted by a bolt 14 to a bracket 15, Fig. 5, the latter being fastened in a horizontal position to the bed of the lathe and extending transversely thereof, as more clearly shown in Fig. 8. One end of the lever 12 terminates in a vertical extension ll having a horizontal plate 16 attached thereto which is adjacent to the bottom face 51 of the plunger 54, as seen in Figs. 6, '7 and 8. The opposite end of the lever 12 terminates in a portion 18, the lower edge of which is adapted to seat in a recess or slot 82 formed transversely of a rod 82, Figs. 4 and 8. The rod 82 extends rearwardly of the turret, as shown in Fig. 5, and is connected in the customary fashion to a clutch indicated generally at 84, which controls the operation of the lathe, the rod being held in an operative position, that is, with the clutch engaged by means of the terminal end 18 of the lever 12 which engages the slot 80. A coiled spring 86, surrounding the rod 80, urges it rearwardly to disengage the clutch. It is apparent from the aforesaid construction, that if the lever 12 is tipped in a counterclockwise direction, as viewed in Fig. 8, to disengage the terminal portion 18 from the slot 82, the rod 88 will be released and will be moved rearwardly by the spring 86 in the direction of the clutch 84, as shown in Fig. 5 to declutch the lathe and cause it to stop.

In operation, the machine is initially adjusted so that the cutting tool 30 will take off the required amount of stock from the rough piece W, for example, reduces its diameter to that shown at F, as shown in Fig. 3. As soon as the initial cut is made, the bearings 36 and 38 are adjusted inwardly so that they are in tangential contact with the newly cut surface F, as shown in Fig. 8'and hence, support the free end of the work against the forces produced by the cutting action of the cutter 30. The automatic stop is then set by retracting the plunger 54, this being done by grasping the hand hold 64 and pulling the rod 56 upwardly and then tipping the member 44 inwardly to engage the hook 56 with the annular recess 54 in the plunger 54. This will bring the arm 42 into the position shown in Fig. 3, with one surface thereof slightly in advance of the plane of the forward surfaces of the bearings 38 and 38. As thus set up, if for any reason, the tool 39 breaks or is dislocated so that it does not remove stock down to the diameter F, the uncut portion of the work will strike the arm 42 and tip it about its pivot 46, thereby disengaging the book 66 from the annular recess 54 on the plunger 54. When this occurs, the spring 58 being released will force the plunger 54 downwardly, Fig. '7, and hence, tip the lever 12 in a counter-clockwise direction about its pivot 14, thereby removing the terminal end 18 from the slot 82. This releases the rod which will fly rearwardly under the influence of the spring 86 to disengage 5 the clutch 84- and stop the lathe before the uncut portion of the work reaches the bearings 36 and 38, and hence, no damage will take place.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

In a power driven lathe having a rotatably supported workpiece, a cutting tool relatively fed to the same in the direction of the longitudinal axis of the workpiece, steadying bearings adapted to engage a finished portion of the work rearwardly of a cutting tool and a power source for the lathe, the combination therein of a sleeve fixed to the lathe, a plunger slidable therein, spring means within the sleeve biasing the plunger in one direction, a member pivoted on said sleeve and adapted to engage said plunger for latching the plunger when it is moved to a cooked position against said spring, an arm on said member having a portion adapted to be positioned in the out between the tool and bearings for engagement by an uncut portion of the workpiece in the event of casualty to the cutting operation to actuate said member to unlatch the lunger, and eans'including a clutch actuating element in the path of said plunger and adapted to be actuated by the same upon the release of the same to thereby declutch the lathe from the power source.

JOHN GEORGE MADSON.

REFERENCES orrEn The following references are of record in the file of this patent: 

